(1) A highly fluorescent derivative of fluorescein amine was prepared from fluorescein amine to detect the presence of carbonyl groups in oxidatively modified proteins. Glutamine synthetase oxidized by MFO systems reacts with this dye to give a dye-protein conjugate under reductive coupling conditions which can be visualized as fluorescent bands after SDS-PAGE; but this dye does not seem to be applicable to other oxidatively modified proteins. (2) Several new types of potent inhibitors of HIV were synthesized and tested for inhibitory activity to HIV. (i) Phosphorothioate oligodeoxynucleotide analogs conjugated with EDTA (S-ODN-EDTA) may produce hydroxyradical in the presence of Fe(II) to cause irreversible damage to the corresponding complementary sequence of RNA. (ii) To increase its affinity for the target sequence, the S-ODN-EDTA derivative was linked with a strong intercalator such as acrylidine. The S-ODN-EDTA conjugate and S-ODN were equally effective in inhibiting the cytopathic effects of HIV-infected T4cells. Moreover, the EDTA conjugate was less effective in inhibiting gagprotein synthesis in chronically HIV-infected cells.